import turtle
def koch(size,n):
    if n==0:
        turtle.fd(size)
    else:
        for angle in[0,60,-120,60]:
            turtle.left(angle)
            koch(size/3,n-1)
def main():
    turtle.setup(800,400)
    turtle.speed(0)#控制绘制速度
    turtle.penup()
    turtle.goto(-300,-50)
    turtle.pendown()
    turtle.pensize(2)
    koch(600,6)#0阶科赫曲线长度，阶数
    turtle.hideturtle()
main()
